This invention relates to an apparatus for continuously producing bulk mesophase (mesophase agglomerates), which is a useful carbonaceous material, from a heavy oil.
When a hydrocarbonaceous heavy oil such as a petroleum heavy oil, coal tar, or oil sand is carbonized by heat treatment at 400.degree. to 500.degree., microcrystals called mesophase microspheres are formed in the heat-treated pitch obtained at an early stage of the process. These mesophase microspheres are liquid crystals having a characteristic molecular arrangement. These mesophase microspheres are carbonaceous precursors which can be converted into highly crystalline carbonized products by subjecting them to further heat treatment. At the same time, since these mesophase microspheres themselves have high chemical and physical activities, great expectations are being held for their utilization for a wide scope of applications having high added values such as that as starting materials for high-quality carbon materials and starting materials for carbon fibers, binders, adsorbents, etc., after being isolated from the above mentioned heat-treated pitch. Isolated mesophase microspheres are generally called mesocarbon microbeads.
For isolation of such mesophase microspheres, a method in which only the pitch matrix containing these microspheres dispersed therein is selectively dissolved in quinoline, pyridine, or an aromatic oil such as anthracene oil, solvent naptha, or the like, and the mesophase microspheres as an insoluble component are isolated by solid-liquid separation has heretofore been proposed. However, in order to carry forward the heat treatment while avoiding formation of coke, the content of the mesophase microspheres in the heat-treated pitch (as determined quantitatively as quinoline-insoluble component according to Japanese Industrial Standards designation JIS K 2425,) can be elevated to only about 15 percent by weight at the most.
Furthermore, a quantity of the solvent for separation of the mesophase microspheres which is 30 times or more by weight that of the heat-treated pitch becomes necessary. Accordingly, in the method for isolating the mesophase microspheres by selective dissolution of the matrix pitch as described above (hereinafter sometimes referred to as "solvent separation method"), it is necessary to use a solvent in a quantity which is 200 times or more by weight that of the mesophase microspheres to be obtained, whereby it has been considered inevitable that the productivity will be very low.
With respect to these problems, it occurred to us that the mesophase as a molding material might not necessarily be in the form of microspheres. Accordingly, we have previously developed a method in which, by imparting a turbulent-flow state to pitch containing mesophase microspheres, the mesophase microspheres are caused to coalesce and to undergo sedimentation separation as agglomerated mesophase. This method has been proposed this disclosed in U.S. patent application Ser. No. 382,360, filed 05/26/82, now U.S. Pat. No. 4,488,957, issued Dec. 19, 1984, in which priority was claimed, based upon Japanese Pat. Application No. 83965/1981, filed 06/01/81.